1. Field of the Invention
The present invention relates to nanotechnology, and particularly, to a method for synthesizing nanodiamonds from graphite powders by high energy ball milling.
2. Description of the Related Art
Carbon is stabilized in various multi-atomic structures with different molecular configurations called allotropes. Allotropes of carbon include, for example, fullerenes, carbon nanotubes (CNTs), graphene, diamond, and nanodiamonds (NDs). Graphite and diamond are two natural crystalline allotropic forms of carbon. Early studies concerning the fabrication of NDs involved fabrication under extreme high pressure and elevated temperature using detonation technique. When detonation is used, a large amount of non-diamond carbon is also often produced, which severely limits application of the NDs that may be present in the product. In addition to detonation technique, NDs have been successfully synthesized in the last five years by laser ablation, plasma enhanced chemical vapor deposition (PECVD), autoclave synthesis from supercritical fluids, chlorination of carbides and ion irradiation of graphite. Many of the current approaches for fabrication of nanodiamonds require the application of either extremely high pressure or high temperature or both. While the plasma process has resulted in homogeneous nucleation of diamonds at lower pressure and temperatures, the nanodiamonds produced using the plasma process are typically large particles with an average size of 100 nm in diameter. Accordingly, it would be desirable to develop a new cost-effective process for synthesizing large amounts of ultrafine nanodiamonds with narrow nanoparticle size distributions at ambient temperature and atmospheric pressure.
Thus, a process for preparing nanodiamonds solving the aforementioned problems is desired.